Light emitting device

ABSTRACT

A light emitting device includes a carrier, a light emitting element disposed and electrically connected to the carrier, and a transparent plate disposed on the carrier and including a flat-portion and a lens-portion. The lens-portion covers the light emitting element and has a light incident surface, a light emitting surface, a first side surface and a second side surface. The light emitting element is adapted to emit a beam. A first partial beam of the beam passes through the light incident surface and emerges from the light emitting surface. A second partial beam of the beam passes through the light incident surface and is transmitted to the first side surface or the second side surface, and the first side surface or the second side surface reflects at least a part of the second partial beam of the beam which then emerges from the light emitting surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of and claims thepriority benefit of Ser. No. 12/610,371, filed on Nov. 2, 2009, nowpending, which claims the priority benefit of Taiwan application serialno. 98105180, filed on Feb. 18, 2009. This application also claims thepriority benefit of Taiwan application serial no. 98137149 filed on Nov.2, 2009. The entirety of each of the above-mentioned patent applicationsis hereby incorporated by reference herein and made a part of thisspecification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a light emitting device, and more particularly,to a light emitting device with a better light emitting uniformity andefficiency.

2. Description of Related Art

A light emitting diode (LED) is a light emitting element constituted bya semiconductor material having group III-V elements. The LED hasadvantages such as long service life, small volume, high shockresistance, low heat output, and low power consumption. Thus, it hasbeen widely utilized in indicators or light sources for householdappliances and various instruments. In recent years, the LED has beendeveloped towards multicolor and high brightness; therefore, itsapplication scope has been expanded to large outdoor display boards,traffic signal lights, and the like. In the future, the LED may evenbecome the main illumination light source with both power-saving andenvironment-protecting functions.

In the designs of conventional LED illumination modules, the light beamemitted by the LED is projected directly. In other words, the light beamgenerated by the LED has high directivity, and thus may result inunfavorable light uniformity and glares that would cause discomfort ofthe user. Moreover, when the LEDs of multiple colors are combined, asthe light from these LEDs is emitted forward directly, a large lightmixing area is needed to harmonize the light. The size of the whole LEDillumination device is increased as a consequence, which causesinconvenience.

To resolve the aforementioned problems, optical glass is usuallycooperated in the current LED illumination modules, so that the lightbeam emitted by the LED can be utilized effectively. However, if theoptical glass is covered on the LED, then an illumination anglegenerated by the entire LED illumination module may be too small orfocused at a certain region, while even having problems such asnon-uniform light or low color render index of the light source.

SUMMARY OF THE INVENTION

An embodiment of the invention provides a light emitting device, whichincludes a transparent plate for enhancing the light emitting uniformityof the light emitting device.

An embodiment of the invention provides a light emitting device, whichincludes a carrier, a light emitting element, and a transparent plate.The light emitting element is disposed and electrically connected to thecarrier. The transparent plate is disposed on the carrier. Thetransparent plate includes a flat-portion and a lens-portion. Theflat-portion has an upper surface and a lower surface which is relativeto the upper surface. Moreover, the lower surface is tightly adhered onthe carrier. The lens-portion covers the light emitting element, and hasa light incident surface, a light emitting surface that is relative tothe light incident surface, and a first side surface and a second sidesurface connecting the upper surface and the light emitting surface. Thelight emitting element is adapted to emit a light beam. Moreover, afirst partial beam of the light beam passes through the light incidentsurface and emerges from the light emitting surface. A second partialbeam of the light beam passes through the light incident surface and istransmitted to the first side surface or the second side surface. Thefirst side surface or the second side surface reflects at least a partof the second partial beam of the light beam, and the part of the secondpartial beam emerges from the light emitting surface.

According to an embodiment of the invention, the first side surface andthe second side surface are planes.

According to an embodiment of the invention, tilting angles of the firstside surface and the second side surface relative to the upper surfaceare substantially different or the same.

According to an embodiment of the invention, the first side surface andthe second side surface are respectively a plane and a curved surface.

According to an embodiment of the invention, the light incident surfaceis a curved surface concaving towards the light emitting surface.

According to an embodiment of the invention, a material of thetransparent plate includes polymethyl methacrylate (PMMA).

According to an embodiment of the invention, the transparent plate isdisposed on the carrier by adhering, screwing, or locking.

According to an embodiment of the invention, the flat portion of thetransparent plate further includes a recess, which is disposed aroundthe lower surface, and the recess is disposed around the light emittingelement.

According to an embodiment of the invention, a waterproof gel layer isdisposed within the recess.

According to an embodiment of the invention, the light emitting elementincludes a surface mount device (SMD) LED.

Another embodiment of the invention provides a light emitting device,which includes a carrier, a light emitting element, and a transparentplate. The light emitting element is disposed and electrically connectedto the carrier. The transparent plate is disposed on the carrier. Thetransparent plate includes a flat-portion and a lens-portion. Theflat-portion has an upper surface and a lower surface that is relativeto the upper surface. Moreover, the lower surface of the flat-portion istightly adhered on the carrier. The lens-portion covers the lightemitting element and has a light incident surface, and a side surfaceand an outer curved surface that are connected to the upper surface. Thelight emitting element is adapted to emit a light beam. A first partialbeam of the light beam passes through the light incident surface andemerges from the outer curved surface. Moreover, a second partial beamof the light beam passes through the light incident surface and istransmitted to the side surface. The side surface reflects at least apart of the second partial beam of the light beam and the part of thesecond partial beam emerges from the outer curved surface.

According to an embodiment of the invention, the light incident surfaceis a curved surface concaving towards the outer curved surface.

According to an embodiment of the invention, a curvature of the lightincident surface and a curvature of the outer curved surface aresubstantially different.

According to an embodiment of the invention, a material of thetransparent plate includes PMMA.

According to an embodiment of the invention, the transparent plate isdisposed on the carrier by adhering, screwing, or locking.

According to an embodiment of the invention, the flat portion of thetransparent plate further includes a recess, which is disposed aroundthe lower surface, and the recess is circularly disposed around thelight emitting element.

According to an embodiment of the invention, a waterproof gel layer isdisposed within the recess.

According to an embodiment of the invention, the light emitting elementincludes a SMD LED.

Another embodiment of the invention provides a light emitting device,which includes a carrier, at least a light emitting element, atransparent plate, and a light shielding side wall structure. The lightemitting element is disposed on the carrier and electrically connectedto the carrier. The transparent plate is disposed on the carrier andincludes a flat-portion and at least one lens-portion. The flat-portionhas an upper surface and a lower surface that is opposite to the uppersurface. Moreover, the lower surface is tightly adhered on the carrier.The lens-portion covers the light emitting element. The light shieldingside wall structure is disposed on the upper surface of the flat-portionand surrounds the lens-portion.

According to an embodiment of the invention, the at least one lightemitting element is a plurality of light emitting elements, the at leastone lens-portion is a plurality of lens-portions. These lens-portionsrespectively cover light emitting elements, and these lens-portions arealigned into a plurality of rows and a plurality of columns to form atwo-dimensional array. The light shielding side wall structure includesan outer reflective frame, a plurality of first reflective partitionplates, and a plurality of second reflective partition plates. The outerreflective frame is disposed on the upper surface of the flat-portionand surrounds the lens-portion. The first reflective partition platesare disposed on the upper surface of the flat-portion, wherein each ofthe first reflective partition plates is disposed between the twoneighboring columns. The second reflective partition plates are disposedon the upper surface of the flat-portion, wherein each of the secondreflective partition plates is disposed between the two neighboringrows.

In light of the foregoing, in the embodiment of the invention, the lightemitting element is covered by the lens-portion of the transparentplate, so that the first partial beam of the light beam emitted by thelight emitting element passes through the light incident surface and thelight emitting surface with different curvatures. The second partialbeam of the light beam passes through the light incident surface and istransmitted to a cut-off surface. Moreover, the cut-off surface allows apart of the second partial beam to passes through the light emittingsurface. Therefore, not only are the light intensity and the lightemitting uniformity of the light emitting device enhanced, but theilluminance distribution of the light emitting element can also becontrolled through the cut-off surface. Also, the occurrence of glaresand double-visions can be prevented for the light emitting device toachieve a better illumination effect. Furthermore, in the embodiment ofthe invention, the light shielding side wall structure is adopted to cutoff or reflect the beam having the large emitting angle emerging fromthe lens-portion. Accordingly, the light emitting device has a smalleremitting angle.

In order to make the aforementioned and other features and advantages ofthe invention more comprehensible, several embodiments accompanied withfigures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1A is a schematic top view of a light emitting device according toan embodiment of the invention.

FIG. 1B is a schematic side view taken along line I-I in FIG. 1A.

FIG. 1C is a schematic back-side view of the transparent plate depictedin FIG. 1A.

FIG. 1D is a schematic side view of a light emitting device according toanother embodiment of the invention.

FIG. 2A is a schematic top view of a light emitting device according toanother embodiment of the invention.

FIG. 2B is a schematic side view taken along line II-II in FIG. 2A.

FIG. 2C is a schematic back-side view of the transparent plate depictedin FIG. 2A.

FIG. 3A is a schematic top view of a light source module according to anembodiment of the invention.

FIG. 3B is a schematic side view taken along line III-III in FIG. 3A.

FIG. 3C is a schematic back-side view of the transparent plate depictedin FIG. 3A.

FIG. 3D is a schematic diagram of the light intensity distribution ofthe light source module depicted in FIG. 3A.

FIG. 4A is a schematic top view of a light source module according toanother embodiment of the invention.

FIG. 4B is a schematic side view taken along line IV-IV in FIG. 4A.

FIG. 4C is a schematic back-side view of the transparent plate depictedin FIG. 4A.

FIG. 4D is a schematic diagram of the light intensity distribution ofthe light source module depicted in FIG. 4A.

FIG. 5A is a schematic top view of a light emitting device according toanother embodiment of the invention.

FIG. 5B is a schematic side view taken along line I-I in FIG. 5A.

FIG. 6A is a schematic top view of a light emitting device according toanother embodiment of the invention.

FIG. 6B is a schematic side view taken along line I-I in FIG. 6A.

FIG. 6C is a perspective view of the light emitting device of FIG. 6A.

FIG. 7A is a light emitting intensity distribution of the light emittingdevice without the light shielding side wall structure and thetransparent plate 230 in FIG. 6A.

FIG. 7B is the light emitting intensity distribution of the lightemitting device in FIG. 6A.

DESCRIPTION OF EMBODIMENTS

FIG. 1A is a schematic top view of a light emitting device according toan embodiment of the invention. FIG. 1B is a schematic side view takenalong line I-I in FIG. 1A. FIG. 1C is a schematic back-side view of thetransparent plate depicted in FIG. 1A. Referring to FIG. 1A, FIG. 1B,and FIG. 1C simultaneously, in the present embodiment, a light emittingdevice 100 includes a carrier 110, a light emitting element 120, and atransparent plate 130.

In details, the light emitting element 120 is disposed and electricallyconnected to the carrier 110. In the present embodiment, the lightemitting element 120 is a light emitting diode (LED), and morespecifically, this LED is a surface mount device (SMD) LED.

The transparent plate 130 is disposed on the carrier 110 and covers thelight emitting element 120. Moreover, the transparent plate 130 includesa flat-portion 132 and a lens-portion 134, which is connected to theflat-portion 132. The flat-portion 132 has an upper surface 132 a, alower surface 132 b that is opposite to the upper surface 132 a, and arecess 132 c, which is disposed around the lower surface 132 b. Herein,the lower surface 132 b of the flat-portion 132 is tightly adhered onthe carrier 110, and the recess 132 c is circularly disposed around thelight emitting element 120. Moreover, the lens-portion 134 includes alight incident surface 134 a, a light emitting surface 134 b that isrelative to the light incident surface 134 a, and a first side surface134 c and a second side surface 134 d that are connecting the uppersurface 132 a and the light emitting surface 134 b. The light incidentsurface 134 a is a curved surface concaving towards the light emittingsurface 134 b. In addition, the first side surface 134 c is a plane andthe second side surface 134 d is a curved surface.

In the present embodiment, the light emitting element 120 is adapted toemit a light beam L. Moreover, a first partial beam L1 of the light beamL passes through the light incident surface 134 a and emerges from thelight emitting surface 134 b. A second partial beam L2 of the light beamL passes through the light incident surface 134 a and is transmitted tothe first side surface 134 c or the second side surface 134 d. The firstside surface 134 c or the second side surface 134 d is adapted toreflect at least a part of the second partial beam L2 of the light beamL to be passed through the light emitting surface 134 b. In other words,after the second partial beam L2 enters the lens-portion 134 through thelight incident surface 134 a, a part of the second partial beam L2 isreflected by the first side surface 134 c or the second side surface 134d, and passes through the light emitting surface 134 b. However, anotherpart of the second partial beam L2 is refracted and passes through thelight emitting surface 134 b. The first side surface 134 c or the secondside surface 134 d reflects a part of the second partial beam L2 of thelight beam L to change a transmission path of a part of the secondpartial beam L2. Therefore, a part of the second partial beam L2 thathas been reflected by the first side surface 134 c or the second sidesurface 134 d focuses and emerges from the lens-portion 134.

Moreover, the flat-portion 132 of the transparent plate 130 of thepresent embodiment includes the recess 132 c. The recess 132 c is filledwith a waterproof gel layer G for achieving a waterproof effect, so thatelectronic elements on the light emitting element 120 and the carrier110 are prevented from being damaged by water, and the electricalquality of the light emitting device 100 can be ensured.

It should be noted that in the present embodiment, a material of thetransparent plate 130 is polymethyl methacrylate (PMMA), which hastransparency. Moreover, the transparent plate 130 can be adhered on thecarrier 110 through adhesion, but the present embodiment is not limitedherein. In other embodiment, the transparent plate 130 can also bedisposed on the carrier 110 through screwing (not shown) or locking (notshown).

In brief, in the present embodiment, the first partial beam L1 of thelight beam L that is emitted by the light emitting element 120 passesthrough the light incident surface 134 a and the light emitting surface134 b sequentially to be transmitted to the external environment. On theother hand, the second partial beam L2 of the light beam L passesthrough the light incident surface 134 a, and is transmitted to thefirst side surface 134 c or the second side surface 134 d. The firstside surface 134 c or the second side surface 134 d is adapted toreflect at least a part of the second partial beam L2 to be passedthrough the light emitting surface 134 b and transmitted to the externalenvironment. In the process, a curvature of the light emitting surface134 b and a curvature of the light incident surface 134 a of thetransparent plate 130 are different. In addition, the first side surface134 c or the second side surface 134 d allows a part of the secondpartial beam L2 to focus. Therefore, when the light beam L, which isemitted by the light emitting element 120, passes the secondary opticaleffect of the transparent plate 130 and is transmitted to the externalenvironment, not only are the light emitting efficiency and lightintensity of the light emitting device 100 enhanced, but the lightemitting uniformity thereof is also enhanced. Additionally, thetransparent plate 130 further controls the illuminance distribution ofthe light emitting element 120 while preventing the occurrence of glaresand double visions, so that the light emitting device 100 can obtain abetter illumination effect.

It should be noted that in other embodiments, as illustrated in FIG. 1D,a lens-portion 134″ includes a light incident surface 134 a, and anouter curved surface 134 d″ and a side surface 134 e′ that are connectedto a upper surface 132 a. Here, a curvature of the outer curved surface134 d″ and a curvature of the light incident surface 134 a aresubstantially different. Specifically, the lens-portion 134″ of atransparent plate 130″ in the present embodiment applies an opticalsimulation method to design the curvatures of the outer curved surface134 d″ and the light incident surface 134 a. Thus, in the process of thelight beam L, which is emitted by a light emitting element 120, to passthrough the light incident surface 134 a and the outer curved surface134 d″, as the light incident surface 134 a and the outer curved surface134 d″ have curvatures that are substantially different, the lightemission uniformity of the light emitting element 120 can be enhanced.Furthermore, as the transparent plate 130″ includes the side surface 134e′, a light emitting device 100″ not only controls the illuminancedistribution of the light emitting element 120 through the side surface134 e′, but also increases the light emitting quantity of the lightemitting element 120 to enhance the light emitting efficiency of thelight emitting element 120 and thereby enhancing the light emittingbrightness of a light emitting device 100″. Furthermore, the occurrenceof glares and double visions is prevented for the light emitting device100″ to obtain a better illumination effect.

FIG. 2A is a schematic top view of a light emitting device according toanother embodiment of the invention. FIG. 2B is a schematic side viewtaken along line II-II in FIG. 2A. FIG. 2C is a schematic back-side viewof the transparent plate depicted in FIG. 2A. Referring to FIG. 2A, FIG.2B, and FIG. 2C simultaneously, in the present embodiment, a lightemitting device 100′ in FIG. 2A is similar to the light emitting device100 in FIG. 1A. However, the main difference between the two is that ina transparent plate 130′ of the light emitting device 100′ in FIG. 2A, atransparent portion 134′ thereof includes a light emitting surface 134b′ which is relative to a light incident surface 134 a, and a first sidesurface 134 e and a second side surface 134 d′ that are opposite to eachother and connecting a upper surface 132 a and the light emittingsurface 134 b′. Herein, the first side surface 134 d′ and the secondside surface 134 e are each a plane, and the light incident surface 134a is a curved surface concaving towards the light emitting surface 134b′.

In details, tilting angles of the first side surface 134 e and thesecond side surface 134 d′ relative to the upper surface 132 a aresubstantially different. In other words, a slope of the first sidesurface 134 e and a slope of the second side surface 134 d′ aredifferent, but the present embodiment is not limited thereto. Obviously,in other embodiments that are not shown, the slopes of the first sidesurface 134 e and the second side surface 134 d′ can also be the same.In the present embodiment, the light emitting element 120 is adapted toemit a light beam L. Moreover, a first partial beam L1 of the light beamL passes through the light incident surface 134 a and is refracted fromthe light emitting surface 134 b′. A second partial beam L2 of the lightbeam L passes through the light incident surface 134 a and istransmitted to the first side surface 134 e or the second side surface134 d′. The first side surface 134 e or the second side surface 134 d′reflects at least a part of the second partial beam L2 of the light beamL to be passed through the light emitting surface 134 b′.

It should be illustrated that the slopes of the first side surface 134 eand the second side surface 134 d′ are different. Moreover, the firstside surface 134 e and the second side surface 134 d′ are used toreflect a part of the second partial beam L2 of the light beam L forchanging a transmission path of a part of the second partial beam L2.Hence, a part of the partial beam L2 that is reflected by the first sidesurface 134 e and the second side surface 134 d′ then focuses.Furthermore, the light emitting device 100′ controls the illuminancedistribution of the light emitting element 120 through the first sidesurface 134 e and the second side surface 134 d′. At the same time, theoccurrence of glares and double visions is prevented so that the lightemitting device 100′ can obtain a better illumination effect.

Besides, in the present embodiment, the lens-portion 134′ applies theoptical simulation method to design the curvatures of the light emittingsurface 134 b′ and the light incident surface 134 a. Therefore, when thelight beam L, which is emitted by the light emitting element 120, passesthrough the secondary optical effect of the light incident surface 134 aand the light emitting surface 134 b′ of the transparent plate 130′, andis transmitted to the external environment, not only is the lightemitting quantity of the light emitting element 120 increased to enhancethe light emitting efficiency thereof, but the light emitting intensityand light uniformity of the light emitting device 100′ can also beenhanced for the light emitting device 100′ to obtain a betterillumination effect.

FIG. 3A is a schematic top view of a light source module according to anembodiment of the invention. FIG. 3B is a schematic side view takenalong line in FIG. 3A. FIG. 3C is a schematic back-side view of thetransparent plate depicted in FIG. 3A. FIG. 3D is a schematic diagram ofthe light intensity distribution of the light source module depicted inFIG. 3A. Referring to FIG. 3A, FIG. 3B, and FIG. 3C simultaneously, inthe present embodiment, a light source module 200 includes a carrier210, a plurality of light emitting elements 220, and a transparent plate230.

In details, the light emitting elements 220 are disposed andelectrically connected to the carrier 210. Specially, in the presentembodiment, the light emitting elements 220 are arranged on the carrier210 in a manner of an 8×6 area array. Moreover, the light emittingelements 220 are a plurality of SMD LEDs.

The transparent plate 230 is disposed on the carrier 210. In addition,the transparent plate 230 includes a flat-portion 232 and a plurality oflens-portions 234, which is connected to the flat-portion 232. Theflat-portion 232 includes an upper surface 232 a, a lower surface 232 bthat is relative to the upper surface 232 a, and a recess 232 c, whichis disposed around the lower surface 232 b. Herein, the lower surface232 b of the flat-portion 232 is tightly adhered on the carrier 210, andthe recess 232 c is circularly disposed around the light emittingelements 220. The lens-portions 234 cover the light emitting elements220 respectively, that is, the lens-portions 234 are also arranged inthe manner of an 8×6 area array. More specifically, every lens-portion234 has a light incident surface 234 a, a light emitting surface 234 bthat is relative to the light incident surface 234 a, and a first sidesurface 234 c and a second side surface 234 d which are connected to theupper surface 232 a. Herein, the first side surface 234 c and the secondside surface 234 d are respectively a plane and a curved surface. Thelight incident surface 234 a is a curved surface concaving towards thelight emitting surface 234 b.

In the present embodiment, each light emitting element 220 is adapted toemit a light beam L′. Moreover, a first partial beam L1′ of the lightbeam L′ passes through the light incident surface 234 a and emerges fromthe light emitting surface 234 b. A second partial beam L2′ of the lightbeam L′ passes through the light incident surface 234 a and istransmitted to the first side surface 234 c or the second side surface234 d. The first side surface 234 c or the second side surface 234 d isadapted to reflect at least a part of the second partial beam L2′ to bepassed through the light emitting surface 234 b. In other words, afterthe second partial beam L2′ enters the lens-portion 234 through thelight incident surface 234 a, a part of the second partial beam L2′ isreflected by the first side surface 234 c or the second side surface 234d, and passes through the light emitting surface 234 b. On the otherhand, another part of the second partial beam L2′ is refracted. Thefirst side surface 234 c or the second side surface 234 d reflects apart of the second partial beam L2′ of the light beam L′ to change atransmission path of a part of the second partial beam L2′. Therefore, apart of the second partial beam L2′ that has been reflected by the firstside surface 234 c or the second side surface 234 d focuses.

Particularly, as every lens-portion 234 of the transparent plate 230includes the first side surface 234 c and the second side surface 234 d,the light source module 200 not only controls the illuminancedistribution and the light intensity distribution (refer to FIG. 3D) ofthe light emitting elements 220 through the first side surface 234 c andthe second side surface 234 d, but also increases the light emittingquantity of the light emitting elements 220 to enhance the lightemitting efficiency of the light emitting elements 220 and therebyenhancing the light emitting brightness of the light source module 200.Furthermore, the occurrence of glares and double visions is preventedfor the light source module 200 to obtain a more uniformed planar lightsource for achieving a better illumination effect. Moreover, theflat-portion 232 of the transparent plate 230 of the present embodimentincludes the recess 232 c. The recess 232 c is filled with a waterproofgel layer G′ for achieving a waterproof effect, so that electronicelements on the light emitting elements 220 and the carrier 210 areprevented from being damaged by water, and the electrical quality of thelight source module 200 can be ensured.

It should be noted that in the present embodiment, a material of thetransparent plate 230 is PMMA, which includes transparency. Moreover,the transparent plate 230 can be adhered to the carrier 210 throughadhesion, but the present embodiment is not limited herein. In otherembodiments, the transparent plate 230 can also be disposed on thecarrier 210 through screwing (not shown) or locking (not shown).Furthermore, it must be illustrated that the invention does not limitthe number and the arranging manner of the light emitting elements 220.Although the light emitting elements 220 herein are specificallyarranged in the manner of the 8×6 area array, however, in otherembodiments, the number and the arranging manner of the light emittingelements 220 can be modified based on demand. That is, the number of thelight emitting elements 220 may be increased or decreased, and thearranging manner may be altered to change the brightness of the planarlight source and the light intensity distribution. The aforesaid methodwould still be a part of the technical proposal of the invention and notdeparting from the protection range of the invention.

In short, in the present embodiment, the first partial beams L1′ of thelight beams L′ that are respectively emitted by the light emittingelements 220 pass through the light incident surface 234 a and the lightemitting surface 234 b sequentially to be transmitted to the externalenvironment. On the other hand, the second partial beams L2′ of thelight beams L′ pass through the light incident surface 234 a, and aretransmitted to the first side surface 234 c or the second side surface234 d. The first side surface 234 c or the second side surface 234 d isadapted to reflect at least a part of the second partial beam L2′ to bepassed through the light emitting surface 234 b and transmitted to theexternal environment. In the process, a curvature of the light emittingsurface 234 b and a curvature of the light incident surface 234 a aredifferent. In addition, the first side surface 234 c or the second sidesurface 234 d allows a part of the second partial beam L2′ to focus.Therefore, when the light beams L′, which are emitted respectively bythe light emitting elements 220, pass through the secondary opticaleffect of the transparent plate 230 and are transmitted to the externalenvironment, not only are the light emitting efficiency and lightintensity of the light source module 200 enhanced, but the lightemitting uniformity of the light source module 200 is also enhanced.Additionally, the transparent plate 230 further controls the illuminancedistribution and the light intensity distribution of the light emittingelements 220 while preventing the occurrence of glares and doublevisions, so that the light source module 200 can obtain a betterillumination effect.

FIG. 4A is a schematic top view of a light source module according toanother embodiment of the invention. FIG. 4B is a schematic side viewtaken along line IV-IV in FIG. 4A. FIG. 4C is a schematic back-side viewof the transparent plate depicted in FIG. 4A. FIG. 4D is a schematicdiagram of the light intensity distribution of the light source moduledepicted in FIG. 4A. Referring to FIG. 4A, FIG. 4B, and FIG. 4Csimultaneously, in the present embodiment, a light source module 200′ inFIG. 4A is similar to the light source module 200 in FIG. 2A. However,the main difference between the two is that in a transparent plate 230′of the light source module 200′ in FIG. 4A, a lens-portion 234′ thereofincludes a light emitting surface 234 b′ relative to the light incidentsurface 234 a, and a first side surface 234 e and a second side surface234 d′ that are opposite to each other and connecting the upper surface232 a and the light emitting surface 234 b′. Herein, the first sidesurface 234 e and the second side surface 234 d′ are each a plane, andthe light incident surface 234 a is a curved surface concaving towardsthe light emitting surface 234 b′.

In more detail, tilting angles of the first side surface 234 e and thesecond side surface 234 d′ relative to the upper surface 232 a aresubstantially different. In other words, a slope of the first sidesurface 234 e and a slope of the second side surface 234 d′ aredifferent, but the present embodiment is not limited thereto. Obviously,in other embodiments, the slopes of the first side surface 234 e and thesecond side surface 234 d′ can also be the same. In the presentembodiment, each light emitting element 220 is adapted to emit a lightbeam L′. Moreover, a first partial beam L1′ of the light beam L′ passesthrough the light incident surface 234 a and emerges from the lightemitting surface 234 b′. A second partial beam L2′ of the light beam L′passes through the light incident surface 234 a and is transmitted tothe first side surface 234 e or the second side surface 234 d′. Thefirst side surface 234 e or the second side surface 234 d′ reflects atleast a part of the second partial beam L2′ to be passed through thelight emitting surface 234 b′.

The slopes of the first side surface 234 e and the second side surface234 d′ are different. Moreover, the first side surface 234 e and thesecond side surface 234 d′ are used to reflect a part of the secondpartial beam L2′ in the light beam L′ for changing a transmission path apart of the second partial beam L2′. Hence, a part of the partial beamL2′ that is reflected by the first side surface 234 e and the secondside surface 234 d′ then focuses. Additionally, the light source module200′ can control the illuminance distribution and the light intensitydistribution (shown in FIG. 4D) of the light emitting elements 220through the first side surface 234 e and the second side surface 234 d′.At the same time, the occurrence of glares and double visions is alsoprevented, so that the light source module 200′ obtains a more uniformedplanar light source for achieving a better illumination effect.

Besides, in the present embodiment, the lens-portion 234′ applies theoptical simulation method to design the curvatures of the light emittingsurface 234 b′ and the light incident surface 234 a. Therefore, when thelight beams L′, which are emitted by the light emitting elements 220,pass through the secondary optical effect of the light incident surface234 a and the light emitting surface 234 b′ of the transparent plate230′, and are transmitted to the external environment, not only is thelight emitting quantity of the light emitting elements 220 increased toenhance the light emitting efficiency thereof, but the light emittingintensity and light uniformity of the light source module 200′ can alsobe enhanced for the light source module 200′ to obtain a betterillumination effect.

FIG. 5A is a top schematic view of a light emitting device according toanother embodiment of the invention. FIG. 5B is a schematiccross-sectional view taken along Line I-I in FIG. 5A. Referring to FIG.5A and FIG. 5B, the light emitting device 100 a of the presentembodiment is similar to the light emitting device 100 in FIG. 1A, andthe main difference therebetween is that the light emitting device 100 aof the present embodiment further includes a light shielding side wallstructure 140. The light shielding side wall structure 140 is disposedon the upper surface 132 a of the flat-portion 132 and surrounds thelens-portion 134. In the present embodiment, the material of the lightshielding side wall structure 140, for example, is metal, metal alloy,polymer plastic material, glass, or the combination thereof.

In the light emitting device 100 a of the present embodiment, the lightshielding side wall structure 140 is adopted to cut off or reflect apart of the light beam having the large emitting angle emitted from thelens-portion 134. Accordingly, the light emitting device 100 a has asmaller emitting angle.

It should be noted that the light shielding side wall structure 140 isnot limited to be applied to the structure of the light emitting device100 in FIG. 1A to form the light emitting device of the presentembodiment. In other embodiments, the light shielding side wallstructure 140 may be applied to the structure of the light emittingdevice 100″ in FIG. 1D or the structure of the light emitting device100′ in FIG. 2A.

FIG. 6A is a top schematic view of a light emitting device according toanother embodiment of the invention. FIG. 6B is a schematiccross-sectional view taken along Line I-I in FIG. 6A. FIG. 6C is athree-dimensional view of the light emitting device in FIG. 6A.Referring to FIGS. 6A-6C, the light emitting device 200 a of the presentembodiment is similar to the light source module 200 in FIG. 3A, and themain difference therebetween is that the light emitting device 200 a ofthe present embodiment further includes a light shielding side wallstructure 140 a. The material of the light shielding side wall structure140, for example, is metal, metal alloy, polymer plastic material,glass, or the combination thereof. In the present embodiment, theselens-portions 234 are aligned into a plurality of rows and a pluralityof columns to form a two-dimensional array. The light shielding sidewall structure 140 a includes an outer reflective frame 142, a pluralityof first reflective partition plates 144, and a plurality of secondreflective partition plates 146. The outer reflective frame 142 isdisposed on the upper surface 232 a of the flat-portion 232 andsurrounds these lens-portions 234. The first reflective partition plates144 are disposed on the upper surface 232 a of the flat-portion 232,wherein each of the first reflective partition plates 144 is disposedbetween the two neighboring columns. The second reflective partitionplates 146 are disposed on the upper surface of the flat-portion 232,wherein each of the second reflective partition plates 146 is disposedbetween the two neighboring rows.

In the light emitting device 200 a of the present embodiment, the lightshielding side wall structure 140 a is adopted to cut off or reflect apart of the light beam having the large emitting angle emitted from thelens-portion 234. Accordingly, the light emitting device 200 a has asmaller emitting angle. Moreover, in the present embodiment, the firstreflective partition plates 144, the second reflective partition plates146, and the outer reflective frame 142 can be formed independently. Asa result, the first reflective partition plates 144, the secondreflective partition plates 146 can be detached from the outerreflective frame 142 or be assembled with the outer reflective frame142. Accordingly, the structure of the light shielding side wallstructure 140 a is easy to be assembled and detached, so that themaintenance is easy. However, in other embodiments, the first reflectivepartition plates 144, the second reflective partition plates 146, andthe outer reflective frame 142 may be integrally formed.

It should be noted that the light shielding side wall structure 140 a isnot limited to be applied to the structure of the light source module200 in FIG. 3A to form the light emitting device 200 a of the presentembodiment. In other embodiments, the light shielding side wallstructure 14 a 0 may be applied to the structure of the light sourcemodule 200′ in FIG. 4A.

FIG. 7A is the light emitting intensity distribution of the lightemitting device without the light shielding side wall structure and thetransparent plate 230 in FIG. 6A. FIG. 7B is the light emittingintensity distribution of the light emitting device in FIG. 6A.Referring to FIG. 7A and FIG. 7B, the radial coordinate represents theamount of the light emitting intensity, the angular coordinaterepresents the light emitting angle, and in these figures, the lightemitting intensity distributions in the first direction and the seconddirection are both illustrated, wherein the first direction is thevertical direction in FIG. 6A, and the second direction is thehorizontal direction in FIG. 6A. It is found by comparing FIG. 7A andFIG. 7B that, in FIG. 7A, the light emitting intensity in the seconddirection between the light emitting angles 30 degrees and 60 degrees isstill larger than a specific value, but in FIG. 7A, the light emittingintensity in the second direction between the light emitting angles 30degrees and 60 degrees is almost equal to zero. Accordingly, it isverified that the light shielding side wall structure 140 a in FIG. 6Acertainty reduces the light emitting angle.

In summary, in the embodiments consistent with the invention, the lightemitting elements of the light emitting devices are covered by thelens-portions of the transparent plates, so that the first partial beamsof the light beams emitted by the light emitting elements sequentiallypass through the light incident surfaces and the light emitting surfacesor the outer curved surfaces with different curvatures. The secondpartial beams of the light beams pass through the light incident surfaceand are transmitted to the side surfaces, the first side surfaces or thesecond side surfaces. Moreover, the side surfaces, the first surfaces orthe second side surfaces reflect at least a part of the second partialbeams and the part of the second partial beams emerge from the lightemitting surfaces or the outer curved surfaces. Hence, not only are thelight intensities and the light emitting uniformities of the lightemitting devices increased, but the illuminance distributions and thelight intensity distributions can also be controlled through the sidesurfaces, the first side surfaces or the second side surfaces. At thesame time, the occurrence of glares and double visions is also preventedfor the light emitting devices to achieve a better illumination effect.In addition, in the embodiment of the invention, the flat-portion of thetransparent plate has the recess, which allows the light emittingelements and the electronic elements on the carrier to be waterproof forensuring the electrical quality of the light emitting devices.Furthermore, in the embodiment of the invention, the light shieldingside wall structure is adopted to cut off or reflect the beam having thelarge emitting angle refracted from the lens-portion. Accordingly, thelight emitting device has a smaller emitting angle.

Although the invention has been described with reference to the aboveembodiments, it will be apparent to one of the ordinary skill in the artthat modifications to the described embodiment may be made withoutdeparting from the spirit of the invention. Accordingly, the scope ofthe invention will be defined by the attached claims not by the abovedetailed descriptions.

What is claimed is:
 1. A light emitting device, comprising: a carrier;at least one light emitting element disposed on the carrier andelectrically connected to the carrier; a transparent plate disposed onthe carrier, the transparent plate comprising: a flat-portion having anupper surface and a lower surface opposite to the upper surface, and thelower surface closed to the carrier; and at least one lens-portioncovering the light emitting element; and a light shielding side wallstructure disposed on the upper surface of the flat-portion andsurrounding the lens-portion; wherein the lens-portion has a lightincident surface, a light emitting surface, a first side surface, and asecond side surface, the light emitting surface being opposite to thelight incident surface, the first side surface and the second sidesurface connecting the upper surface and the light emitting surface, thelight emitting element is adapted to emit a beam, a first partial beamof the beam passes through the light incident surface and emerges fromthe light emitting surface, a second partial beam of the beam passesthrough the light incident surface and is transmitted to the first sidesurface or the second side surface, the first side surface or the secondside surface reflects at least one part of the second partial beam ofthe beam, and the part of the second partial beam emerges from the lightemitting surface, the light shielding side wall structure is adapted toreflect a part of the beam, and first side surface and the second sidesurface are respectively a flat surface and a curved surface.
 2. Thelight emitting device as claimed in claim 1, wherein the at least onelight emitting element is a plurality of light emitting elements, the atleast one lens-portion is a plurality of lens-portions, thelens-portions respectively cover the light emitting elements, thelens-portions are aligned into a plurality of rows and a plurality ofcolumns to form a two-dimensional array, the light shielding side wallstructure comprising: an outer reflective frame disposed on the uppersurface of the flat-portion and surrounding the lens-portion; aplurality of first reflective partition plates disposed on the uppersurface of the flat-portion, wherein each of the first reflectivepartition plates is disposed between the two neighboring columns; and aplurality of second reflective partition plates disposed on the uppersurface of the flat-portion, wherein each of the second reflectivepartition plates is disposed between the two neighboring rows.
 3. Thelight emitting device as claimed in claim 1, wherein the light incidentsurface is a curved surface concaving towards the light emittingsurface.
 4. The light emitting device as claimed in claim 1, wherein amaterial of the transparent plate comprises polymethyl methacrylate. 5.The light emitting device as claimed in claim 1, wherein the transparentplate is disposed on the carrier by adhering, screwing, or locking. 6.The light emitting device as claimed in claim 1, wherein the flatportion of the transparent plate further comprises a recess which isdisposed around the lower surface, and the recess is circularly disposedaround the light emitting element.
 7. The light emitting device asclaimed in claim 6, wherein a waterproof gel layer is disposed withinthe recess.
 8. The light emitting device as claimed in claim 1, whereinthe light emitting element comprises a surface mount device (SMD) lightemitting diode (LED).
 9. A light emitting device, comprising: a carrier;at least one light emitting element disposed on the carrier andelectrically connected to the carrier; a transparent plate disposed onthe carrier, the transparent plate comprising: a flat-portion having anupper surface and a lower surface opposite to the upper surface, and thelower surface closed to the carrier; and at least one lens-portioncovering the light emitting element; and a light shielding side wallstructure disposed on the upper surface of the flat-portion andsurrounding the lens-portion; wherein the lens-portion has a lightincident surface, a light emitting surface, a first side surface, and asecond side surface, the light emitting surface being opposite to thelight incident surface, the first side surface and the second sidesurface connecting the upper surface and the light emitting surface, thelight emitting element is adapted to emit a beam, a first partial beamof the beam passes through the light incident surface and emerges fromthe light emitting surface, a second partial beam of the beam passesthrough the light incident surface and is transmitted to the first sidesurface or the second side surface, the first side surface or the secondside surface reflects at least one part of the second partial beam ofthe beam, and the part of the second partial beam emerges from the lightemitting surface, the light shielding side wall structure is adapted toreflect a part of the beam, and the light incident surface is a curvedsurface concaving towards the light emitting surface.
 10. The lightemitting device as claimed in claim 9, wherein the first side surfaceand the second side surface are flat surfaces.
 11. The light emittingdevice as claimed in claim 10, wherein a tilting angle of the first sidesurface and a tilting angle of the second side surface relative to theupper surface are substantially different or the same.
 12. The lightemitting device as claimed in claim 9, wherein the at least one lightemitting element is a plurality of light emitting elements, the at leastone lens-portion is a plurality of lens-portions, the lens-portionsrespectively cover the light emitting elements, the lens-portions arealigned into a plurality of rows and a plurality of columns to form atwo-dimensional array, the light shielding side wall structurecomprising: an outer reflective frame disposed on the upper surface ofthe flat-portion and surrounding the lens-portion; a plurality of firstreflective partition plates disposed on the upper surface of theflat-portion, wherein each of the first reflective partition plates isdisposed between the two neighboring columns; and a plurality of secondreflective partition plates disposed on the upper surface of theflat-portion, wherein each of the second reflective partition plates isdisposed between the two neighboring rows.
 13. The light emitting deviceas claimed in claim 9, wherein a material of the transparent platecomprises polymethyl methacrylate.
 14. The light emitting device asclaimed in claim 9, wherein the transparent plate is disposed on thecarrier by adhering, screwing, or locking.
 15. A light emitting device,comprising: a carrier; at least one light emitting element disposed onthe carrier and electrically connected to the carrier; a transparentplate disposed on the carrier, the transparent plate comprising: aflat-portion having an upper surface and a lower surface opposite to theupper surface, and the lower surface closed to the carrier, wherein theflat portion of the transparent plate further comprises a recess whichis disposed around the lower surface, and the recess is circularlydisposed around the light emitting element; and at least onelens-portion covering the light emitting element; and a light shieldingside wall structure disposed on the upper surface of the flat-portionand surrounding the lens-portion.
 16. The light emitting device asclaimed in claim 15, wherein the lens-portion has a light incidentsurface, a side surface, and an outer curved surface, the side surfaceand the outer curved surface is connected to the upper surface, thelight emitting element is adapted to emit a beam, a first partial beamof the beam passes through the light incident surface and emerges fromthe outer curved surface, a second partial beam of the beam passesthrough the light incident surface and is transmitted to the sidesurface, the side surface reflects at least one part of the secondpartial beam of the beam, and the part of the second partial beamemerges from the outer curved surface, and the light shielding side wallstructure is adapted to reflect a part of the beam.
 17. The lightemitting device as claimed in claim 16, wherein the light incidentsurface is a curved surface concaving towards the outer curved surface.18. The light emitting device as claimed in claim 16, wherein acurvature of the light incident surface and a curvature of the outercurved surface are substantially different.
 19. The light emittingdevice as claimed in claim 15, wherein a waterproof gel layer isdisposed within the recess.
 20. The light emitting device as claimed inclaim 15, wherein the light emitting element comprises a surface mountdevice (SMD) light emitting diode (LED).